irqchip/aspeed-scu-ic: Refactor driver to support variant-based initialization

The SCU IC driver handles each AST2600 instance with separate
initialization functions and hardcoded register definitions, which is
inflexible and creates duplicated code.

Consolidate the implementation by introducing a variant-based structure,
selected via compatible string, and use a unified init path and MMIO access
via of_iomap().  This simplifies the code and prepares for upcoming SoCs
like AST2700, which require split register handling.

[ tglx: Cleaned up coding style and massaged change log ]

Signed-off-by: Ryan Chen <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/all/[email protected]

Author: aspeedtech

drivers/irqchip/irq-aspeed-scu-ic.c

@@ -7,55 +7,56 @@
  */
 
 #include <linux/bitops.h>
+#include <linux/io.h>
 #include <linux/irq.h>
 #include <linux/irqchip.h>
 #include <linux/irqchip/chained_irq.h>
 #include <linux/irqdomain.h>
-#include <linux/mfd/syscon.h>
+#include <linux/of_address.h>
 #include <linux/of_irq.h>
-#include <linux/regmap.h>
 
-#define ASPEED_SCU_IC_REG		0x018
-#define ASPEED_SCU_IC_SHIFT		0
-#define ASPEED_SCU_IC_ENABLE		GENMASK(15, ASPEED_SCU_IC_SHIFT)
-#define ASPEED_SCU_IC_NUM_IRQS		7
 #define ASPEED_SCU_IC_STATUS		GENMASK(28, 16)
 #define ASPEED_SCU_IC_STATUS_SHIFT	16
 
-#define ASPEED_AST2600_SCU_IC0_REG	0x560
-#define ASPEED_AST2600_SCU_IC0_SHIFT	0
-#define ASPEED_AST2600_SCU_IC0_ENABLE	\
-	GENMASK(5, ASPEED_AST2600_SCU_IC0_SHIFT)
-#define ASPEED_AST2600_SCU_IC0_NUM_IRQS	6
+struct aspeed_scu_ic_variant {
+	const char	*compatible;
+	unsigned long	irq_enable;
+	unsigned long	irq_shift;
+	unsigned int	num_irqs;
+};
+
+#define SCU_VARIANT(_compat, _shift, _enable, _num) {	\
+	.compatible		=	_compat,	\
+	.irq_shift		=	_shift,		\
+	.irq_enable		=	_enable,	\
+	.num_irqs		=	_num,		\
+}
 
-#define ASPEED_AST2600_SCU_IC1_REG	0x570
-#define ASPEED_AST2600_SCU_IC1_SHIFT	4
-#define ASPEED_AST2600_SCU_IC1_ENABLE	\
-	GENMASK(5, ASPEED_AST2600_SCU_IC1_SHIFT)
-#define ASPEED_AST2600_SCU_IC1_NUM_IRQS	2
+static const struct aspeed_scu_ic_variant scu_ic_variants[]	__initconst = {
+	SCU_VARIANT("aspeed,ast2400-scu-ic",	0, GENMASK(15, 0),	7),
+	SCU_VARIANT("aspeed,ast2500-scu-ic",	0, GENMASK(15, 0),	7),
+	SCU_VARIANT("aspeed,ast2600-scu-ic0",	0, GENMASK(5, 0),	6),
+	SCU_VARIANT("aspeed,ast2600-scu-ic1",	4, GENMASK(5, 4),	2),
+};
 
 struct aspeed_scu_ic {
-	unsigned long irq_enable;
-	unsigned long irq_shift;
-	unsigned int num_irqs;
-	unsigned int reg;
-	struct regmap *scu;
-	struct irq_domain *irq_domain;
+	unsigned long		irq_enable;
+	unsigned long		irq_shift;
+	unsigned int		num_irqs;
+	void __iomem		*base;
+	struct irq_domain	*irq_domain;
 };
 
 static void aspeed_scu_ic_irq_handler(struct irq_desc *desc)
 {
-	unsigned int sts;
-	unsigned long bit;
-	unsigned long enabled;
-	unsigned long max;
-	unsigned long status;
 	struct aspeed_scu_ic *scu_ic = irq_desc_get_handler_data(desc);
 	struct irq_chip *chip = irq_desc_get_chip(desc);
-	unsigned int mask = scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT;
+	unsigned long bit, enabled, max, status;
+	unsigned int sts, mask;
 
 	chained_irq_enter(chip, desc);
 
+	mask = scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT;
 	/*
 	 * The SCU IC has just one register to control its operation and read
 	 * status. The interrupt enable bits occupy the lower 16 bits of the
@@ -66,19 +67,17 @@ static void aspeed_scu_ic_irq_handler(struct irq_desc *desc)
 	 * shifting the status down to get the mapping and then back up to
 	 * clear the bit.
 	 */
-	regmap_read(scu_ic->scu, scu_ic->reg, &sts);
+	sts = readl(scu_ic->base);
 	enabled = sts & scu_ic->irq_enable;
 	status = (sts >> ASPEED_SCU_IC_STATUS_SHIFT) & enabled;
 
 	bit = scu_ic->irq_shift;
 	max = scu_ic->num_irqs + bit;
 
 	for_each_set_bit_from(bit, &status, max) {
-		generic_handle_domain_irq(scu_ic->irq_domain,
-					  bit - scu_ic->irq_shift);
-
-		regmap_write_bits(scu_ic->scu, scu_ic->reg, mask,
-				  BIT(bit + ASPEED_SCU_IC_STATUS_SHIFT));
+		generic_handle_domain_irq(scu_ic->irq_domain, bit - scu_ic->irq_shift);
+		writel((readl(scu_ic->base) & ~mask) | BIT(bit + ASPEED_SCU_IC_STATUS_SHIFT),
+		       scu_ic->base);
 	}
 
 	chained_irq_exit(chip, desc);
@@ -87,30 +86,29 @@ static void aspeed_scu_ic_irq_handler(struct irq_desc *desc)
 static void aspeed_scu_ic_irq_mask(struct irq_data *data)
 {
 	struct aspeed_scu_ic *scu_ic = irq_data_get_irq_chip_data(data);
-	unsigned int mask = BIT(data->hwirq + scu_ic->irq_shift) |
-		(scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
+	unsigned int bit = BIT(data->hwirq + scu_ic->irq_shift);
+	unsigned int mask = bit | (scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
 
 	/*
 	 * Status bits are cleared by writing 1. In order to prevent the mask
 	 * operation from clearing the status bits, they should be under the
 	 * mask and written with 0.
 	 */
-	regmap_update_bits(scu_ic->scu, scu_ic->reg, mask, 0);
+	writel(readl(scu_ic->base) & ~mask, scu_ic->base);
 }
 
 static void aspeed_scu_ic_irq_unmask(struct irq_data *data)
 {
 	struct aspeed_scu_ic *scu_ic = irq_data_get_irq_chip_data(data);
 	unsigned int bit = BIT(data->hwirq + scu_ic->irq_shift);
-	unsigned int mask = bit |
-		(scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
+	unsigned int mask = bit | (scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
 
 	/*
 	 * Status bits are cleared by writing 1. In order to prevent the unmask
 	 * operation from clearing the status bits, they should be under the
 	 * mask and written with 0.
 	 */
-	regmap_update_bits(scu_ic->scu, scu_ic->reg, mask, bit);
+	writel((readl(scu_ic->base) & ~mask) | bit, scu_ic->base);
 }
 
 static int aspeed_scu_ic_irq_set_affinity(struct irq_data *data,
@@ -143,21 +141,15 @@ static const struct irq_domain_ops aspeed_scu_ic_domain_ops = {
 static int aspeed_scu_ic_of_init_common(struct aspeed_scu_ic *scu_ic,
 					struct device_node *node)
 {
-	int irq;
-	int rc = 0;
+	int irq, rc = 0;
 
-	if (!node->parent) {
-		rc = -ENODEV;
+	scu_ic->base = of_iomap(node, 0);
+	if (IS_ERR(scu_ic->base)) {
+		rc = PTR_ERR(scu_ic->base);
 		goto err;
 	}
-
-	scu_ic->scu = syscon_node_to_regmap(node->parent);
-	if (IS_ERR(scu_ic->scu)) {
-		rc = PTR_ERR(scu_ic->scu);
-		goto err;
-	}
-	regmap_write_bits(scu_ic->scu, scu_ic->reg, ASPEED_SCU_IC_STATUS, ASPEED_SCU_IC_STATUS);
-	regmap_write_bits(scu_ic->scu, scu_ic->reg, ASPEED_SCU_IC_ENABLE, 0);
+	writel(ASPEED_SCU_IC_STATUS, scu_ic->base);
+	writel(0, scu_ic->base);
 
 	irq = irq_of_parse_and_map(node, 0);
 	if (!irq) {
@@ -166,8 +158,7 @@ static int aspeed_scu_ic_of_init_common(struct aspeed_scu_ic *scu_ic,
 	}
 
 	scu_ic->irq_domain = irq_domain_create_linear(of_fwnode_handle(node), scu_ic->num_irqs,
-						   &aspeed_scu_ic_domain_ops,
-						   scu_ic);
+						      &aspeed_scu_ic_domain_ops, scu_ic);
 	if (!scu_ic->irq_domain) {
 		rc = -ENOMEM;
 		goto err;
@@ -180,61 +171,39 @@ static int aspeed_scu_ic_of_init_common(struct aspeed_scu_ic *scu_ic,
 
 err:
 	kfree(scu_ic);
-
 	return rc;
 }
 
-static int __init aspeed_scu_ic_of_init(struct device_node *node,
-					struct device_node *parent)
+static const struct aspeed_scu_ic_variant *aspeed_scu_ic_find_variant(struct device_node *np)
 {
-	struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
-
-	if (!scu_ic)
-		return -ENOMEM;
-
-	scu_ic->irq_enable = ASPEED_SCU_IC_ENABLE;
-	scu_ic->irq_shift = ASPEED_SCU_IC_SHIFT;
-	scu_ic->num_irqs = ASPEED_SCU_IC_NUM_IRQS;
-	scu_ic->reg = ASPEED_SCU_IC_REG;
-
-	return aspeed_scu_ic_of_init_common(scu_ic, node);
+	for (int i = 0; i < ARRAY_SIZE(scu_ic_variants); i++) {
+		if (of_device_is_compatible(np, scu_ic_variants[i].compatible))
+			return &scu_ic_variants[i];
+	}
+	return NULL;
 }
 
-static int __init aspeed_ast2600_scu_ic0_of_init(struct device_node *node,
-						 struct device_node *parent)
+static int __init aspeed_scu_ic_of_init(struct device_node *node, struct device_node *parent)
 {
-	struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
-
-	if (!scu_ic)
-		return -ENOMEM;
-
-	scu_ic->irq_enable = ASPEED_AST2600_SCU_IC0_ENABLE;
-	scu_ic->irq_shift = ASPEED_AST2600_SCU_IC0_SHIFT;
-	scu_ic->num_irqs = ASPEED_AST2600_SCU_IC0_NUM_IRQS;
-	scu_ic->reg = ASPEED_AST2600_SCU_IC0_REG;
-
-	return aspeed_scu_ic_of_init_common(scu_ic, node);
-}
+	const struct aspeed_scu_ic_variant *variant;
+	struct aspeed_scu_ic *scu_ic;
 
-static int __init aspeed_ast2600_scu_ic1_of_init(struct device_node *node,
-						 struct device_node *parent)
-{
-	struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
+	variant = aspeed_scu_ic_find_variant(node);
+	if (!variant)
+		return -ENODEV;
 
+	scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
 	if (!scu_ic)
 		return -ENOMEM;
 
-	scu_ic->irq_enable = ASPEED_AST2600_SCU_IC1_ENABLE;
-	scu_ic->irq_shift = ASPEED_AST2600_SCU_IC1_SHIFT;
-	scu_ic->num_irqs = ASPEED_AST2600_SCU_IC1_NUM_IRQS;
-	scu_ic->reg = ASPEED_AST2600_SCU_IC1_REG;
+	scu_ic->irq_enable	= variant->irq_enable;
+	scu_ic->irq_shift	= variant->irq_shift;
+	scu_ic->num_irqs	= variant->num_irqs;
 
 	return aspeed_scu_ic_of_init_common(scu_ic, node);
 }
 
 IRQCHIP_DECLARE(ast2400_scu_ic, "aspeed,ast2400-scu-ic", aspeed_scu_ic_of_init);
 IRQCHIP_DECLARE(ast2500_scu_ic, "aspeed,ast2500-scu-ic", aspeed_scu_ic_of_init);
-IRQCHIP_DECLARE(ast2600_scu_ic0, "aspeed,ast2600-scu-ic0",
-		aspeed_ast2600_scu_ic0_of_init);
-IRQCHIP_DECLARE(ast2600_scu_ic1, "aspeed,ast2600-scu-ic1",
-		aspeed_ast2600_scu_ic1_of_init);
+IRQCHIP_DECLARE(ast2600_scu_ic0, "aspeed,ast2600-scu-ic0", aspeed_scu_ic_of_init);
+IRQCHIP_DECLARE(ast2600_scu_ic1, "aspeed,ast2600-scu-ic1", aspeed_scu_ic_of_init);